Suspension systems for vehicles with two or more axles are widely known from the prior art. In fact, the applicant has been the inventor of several suspension systems including that disclosed in U.S. Patent No. 3,614,123 issued Oct. 19, 1971, and incorporated herein by reference.
However, the present invention possesses substantial improvements over those of the prior art. Applicant's design utilizes elastomer load pad spacers to mount the leaf spring to the supporting members of the suspension assembly. Load pads are added to provide additional deflection for the stiffer single leaf springs, serve as load bearings for the required geometric axle articulation, dampen road shocks, and reduce vibration frequencies of free floating leaf springs. In this manner, applicant succeeds in eliminating several bushing assemblies that are required in other designs. As the elastomer load pads are easily clamped and bolted to the ends of the leaf springs, there is no requirement that the ends of the leaf springs be either journaled around a bushing or looped around retaining bolts. By eliminating this extra forming at the ends of the leaf springs, a single thicker spring can be used with adjacent deflection means instead of the multilayered spring previously required.
Furthermore, applicant's design is much less prone to damage because of the simplistic shape of the leaf springs themselves. The journaled or looped ends as used on previous designs are difficult to form correctly and also subject to breakage and misalignment during use. Once a journaled or looped end of a spring is damaged the whole spring must be replaced. However, with the use of elastomeric load pads, failure of only the spring or load pad does not require the replacement of both.
The applicant has also added urethane wear pads to the spring guides on the axles to eliminate metal-to-metal wear during operation.
Other advantages to applicant's design include decreased cost and ease of construction over previous designs because of its simplified leaf spring assemblies and hanger assemblies and the elimination of several bushing assemblies. Maintenance and possible trouble areas are also decreased to a minimum. Additionally, the present invention utilizes the combined flexing of the leaf springs and cooperating elastomers in a unique way to provide an exceptionally stable, yet comfortable ride.
These and other advantages are apparent from the drawing and detailed description to follow.